title: Does immunohistochemistry provide additional prognostic data in gastrointestinal stromal tumors?
abstract: BACKGROUND
  To investigate the predictive and prognostic effects of clinicopathologic and immunohistochemical (IHC) features in patients with gastrointestinal stromal tumours (GISTs).
  
  
  METHODS
  Fifty-six patients who were diagnosed with GIST between 2002 and 2012 were retrospectively evaluated. Relationships between clinicopathologic/immunohistochemical factors and prognosis were investigated.
  
  
  RESULTS
  Median overall survival (OS) of the whole study group was 74.9 months (42.8-107.1 months), while it was 95.2 months in resectable and 44.7 months in metastatic patients respectively (p=0.007). Epitheliolid tumor morphology was significantly associated with shortened OS as compared to other histologies (p=0.001). SMA(+) tumours were significantly correlated with low (<10/50HPF) mitotic activity (p=0.034). Moreover, SMA(+) patients tended to survive longer and had significantly longer disease-free survival (DFS) times than SMA (-) patients (37.7 months vs 15.9 months; p=0.002). High Ki-67 level (≥30%) was significantly associated with shorter OS (34 vs 95.2 months; 95%CI; p=0.001). CD34 (-) tumours were significantly associated with low proliferative tumours (Ki-67<%10) (p=0.026). Median PFS (progression-free survival) of the patients who received imatinib was 36 months (27.7-44.2 months). CD34 (-) patients had significantly longer PFS times than that of negative tumours; (50.8 vs 29.8 months; p=0.045). S100 and desmin expression did not play any role in predicting the prognosis of GISTs. Multivariate analysis demonstrated that ≥10/50HPF mitotic activity/HPF was the only independent factor for risk of death in GIST patients.
  
  
  CONCLUSIONS
  Despite the negative prognostic and predictive effect of high Ki-67 and CD34 expression, mitotic activity remains the strongest prognostic factor in GIST patients. SMA positivity seems to affect GIST prognosis positively. However, large-scale, multicenter studies are required to provide supportive data for these findings.
authors.affiliation: Department of Medical Oncology, Ataturk Training and Research Hospital, Izmir Katip Celebi University, Turkey E-mail : demir.lutfiye77@gmail.com.
authors.forename: Lutfiye
authors.initials: L
authors.lastname: Demir
authors.forename: Nese
authors.initials: N
authors.lastname: Ekinci
authors.forename: Cigdem
authors.initials: C
authors.lastname: Erten
authors.forename: Yuksel
authors.initials: Y
authors.lastname: Kucukzeybek
authors.forename: Ahmet
authors.initials: A
authors.lastname: Alacacioglu
authors.forename: Isil
authors.initials: I
authors.lastname: Somali
authors.forename: Alper
authors.initials: A
authors.lastname: Can
authors.forename: Ahmet
authors.initials: A
authors.lastname: Dirican
authors.forename: Vedat
authors.initials: V
authors.lastname: Bayoglu
authors.forename: Murat
authors.initials: M
authors.lastname: Akyol
authors.forename: Fulya
authors.initials: F
authors.lastname: Cakalagaoglu
authors.forename: Mustafa Oktay
authors.initials: MO
authors.lastname: Tarhan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D005260:Female; D005500:Follow-Up Studies; D046152:Gastrointestinal Stromal Tumors / Q000175:diagnosis* / Q000378:metabolism* / Q000601:surgery; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D012372:ROC Curve; D012189:Retrospective Studies; D015996:Survival Rate
chemical_list: D014408:Biomarkers, Tumor